Introduction: Articular cartilage (AC) is a low friction load bearing material found in synovial joints. The natural repair of damaged tissue is difficult and often requires surgical intervention. With large defects it becomes necessary to match the original tissue geometry. We hypothesized that localized collagen (COL) and/or proteoglycan (PG) remodeling occurs during AC spherical reshaping. The objective of this study was to determine the presence, magnitude and depth dependence of COL and PG remodeling that accompanies AC reshaping. Methods: Full thickness AC blocks (7x7 mm2 surface area) were harvested from the ridges of the patellofemoral groove of immature (1-3 week old) bovine knees. The top 0-1 mm with intact articular surface was sliced off with a vibrating microtome. A 6 mm diameter disk was punched out of the slice and the most anterior edge was notched to mark directionality. The final sample was a 1 mm thick, 6 mm diameter disk with a notch on the most anterior edge. Samples were either not treated (day 0; D0) or allowed to free swell overnight in 20% FBS. Then cultured samples were placed in culture with 20% FBS in either free swelling (FS), static bending with the articular surface concave (concave) or in static bending with the articular surface convex (convex). Wet-weight and opening angle were measured before and 2 hours after removal from culture. Following culture, samples were cut in half in the anterior posterior direction. One half of each sample was frozen and later analyzed for PG, COL and cell content. The other half was fixed for 24-48 hours in 4% paraformaldehyde; samples were then transferred to 20% Hexabrix for 24 hours before imaging by micro-computed tomography (μCT) to assess PG distribution. Following μCT, samples were again placed in 4% paraformaldehyde for 24-48 hours and then prepared for qPLM to assess collagen orientation (α), parallelism index (PI), and area fraction of non-birefringent tissue (AFNBR). Variations were assessed by ANOVA with post hoc tests for significant ANOVA (pResults: Four days of spherical bending significantly changed (pDiscussion: Spherical bending reshapes AC into a cup shape. Trends of decreasing α standard deviation (αSD) with depth in concave samples and increasing αSD with depth in convex samples indicate that COL matrix disorganization is associated with regions of compressive strain. Consequently, further evaluation on the disorganization of the collagen network should be studied to elucidate mechanisms of cartilage reshaping.

<p>Ribosome assembly is a complex process, facilitated by more than 20 protein factors in bacteria. GTPases and ATPases represent the energy driving force of these factors. In my research as a PhD student, I studied the function of two GTPases, YjeQ and RbgA, involved in the assembly of the small and the large ribosomal subunits, respectively.</p> <p>We isolated and characterized <em>in-vivo</em> assembled immature small (30S) and large (50S) subunits using a perturbation in the genes coding for these proteins. We observed that both subunits contained an incomplete ribosomal protein content, mainly lacking late-binding r-proteins. Additionally, we observed distortions in the functional core of the immature ribosomal subunit, particularly in the mRNA decoding center of the 30S subunit, the peptidyltransferase center of the 50S subunit, and tRNA binding sites.</p> <p>Additionally, we have determined that the YjeQ protein interacts with the 30S subunit through its N-terminal OB-fold domain, and C-terminal Zn-finger motif. The binding site of YjeQ on the 30S subunit prevents the interaction with tRNAs, translation factors, and the 50S subunit.</p> <p>Finally, we uncovered a novel functional interplay between RbgA and the ribosomal protein L16 during late stages of ribosomal assembly. We proposed that recruitment of L16 to the assembling 50S subunit would induce a conformational rearrangement that would ultimately promote the GTP-dependent release of RbgA.</p> <p>The function of the assembly factors associated with the process of <em>in-vivo</em> ribosome assembly is not known, and thus a framework on how ribosomes are built is still elusive. I believe the research presented in this thesis provides novel insights into the role of YjeQ and RbgA in the assembly of ribosomes</p> / Doctor of Philosophy (PhD)

The early identification of septically infected newborn infants is important for ensuring good outcomes. Blood cell differentiations are helpful, but they are often time consuming and inaccurate. In this study, we evaluated the use of automatic white blood cell differentiations by flow cytometry for the diagnosis of neonatal sepsis. Episodes of suspected infection in neonates were retrospectively classified into two groups, unlikely infection (UI, levels of Interleukin-6 < 400 pg/mL or CRP within 48 h < 10 mg/L), n = 101 and probable infection (PI, Interleukin-6 ≥ 400 pg/mL or CRP within 48 h ≥ 10 mg/L), n = 98. Complete blood cell counts were performed by Sysmex XN-9000® using flow cytometry. Relative and absolute proportions of immature granulocytes were evaluated. Unexpectedly, the absolute count of immature granulocytes was significantly lower in the group of PI compared to UI neonates. Similar results were found when analysing the relative proportion of immature granulocytes among all neutrophil granulocytes. On the other hand, manually counted immature to total (I/T) ratios of granulocytes were higher in PI than in UI infants. Therefore, we conclude that differentiations of granulocytes by Sysmex XN-9000® can be used to distinguish between infected and uninfected neonates if the results are interpreted according to our findings. A low count of immature granulocytes as determined by Sysmex XN-9000® may indicate neonatal infection.

La chaîne actuelle du Tian Shan (Asie centrale) est considérée comme une conséquence directe de la réactivation d'une ceinture orogénique du Paléozoïque due à la collision Inde-Asie, au Cénozoïque. Un travail détaillé a été réalisé le long du piémont nord de la chaîne en intégrant les observations géologiques de terrain, analyses structurales, profils sismiques, nouvelles mesures des anomalies gravimétriques et des données de forages. Tout d'abord cette étude apporte de nouvelles preuves directes, à différentes échelles, sur l'existence d'un paléo-relief majeur le long du front nord du Tian Shan au cours du Mésozoïque, et plus particulièrement pendant le Jurassique. Deuxièmement, la quantité de raccourcissement calculée à travers cette ceinture de plis et chevauchements nord du Tian Shan est relativement faible et les structures reconnues le long du front de la chaîne présentent une hétérogénéité latérale forte. Ainsi, alors qu'un chevauchement du socle paléozoïque sur les séries sédimentaires mésozoïques et cénozoïques du bassin est remarquablement exposé le long de certaines vallées, d'autres sections montrent que les séries sédimentaires du Trias au Jurassique peuvent être suivies de manière continue, depuis le bassin jusque sur le toit du socle Paléozoïque où ils reposent en discordance relativement haut dans la chaîne. Quatre coupes géologiques ont été construites par l'intégration des données pluridisciplinaires acquises. La restauration de ces coupes montre que les taux de raccourcissement sont inférieurs à 20% et peuvent descendre à un minimum de 6%. Ces observations suggèrent que le piémont nord du Tian Shan est plutôt «jeune» et que la chaîne d'avant pays est encore à un stade primaire de son évolution tectonique. En d'autres termes, le piémont nord du Tian Shan peut être considéré comme un exemple type de front de chaîne immature.

Introduction : Dans le cœur adulte, l'ischémie et la reperfusion entraînent des perturbations électriques, mécaniques, biochimiques et structurales qui peuvent causer des dommages réversibles ou irréversibles selon la sévérité de l'ischémie. Malgré les récents progrès en cardiologie et en chirurgie fœtales, la connaissance des mécanismes impliqués dans la réponse du myocarde embryonnaire à un stress hypoxique transitoire demeure lacunaire. Le but de ce travail a donc été de caractériser les effets chrono-, dromo- et inotropes de l'anoxie et de la réoxygénation sur un modèle de cœur embryonnaire isolé. D'autre part, les effets du monoxyde d'azote (NO) et de la modulation des canaux KATP mitochondriaux (mitoKATP) sur la récupération fonctionnelle postanoxique ont été étudiés. La production myocardique de radicaux d'oxygène (ROS) et l'activité de MAP Kinases (ERK et JNK) impliquées dans la signalisation cellulaire ont également été déterminées.<br />Méthodes : Des cœurs d'embryons de poulet âgés de 4 jours battant spontanément ont été placés dans une chambre de culture puis soumis à une anoxie de 30 min suivie d'une réoxygénation de 60 min. L'activité électrique (ECG), les contractions de l'oreillette, du ventricule et du conotroncus (détectées par photométrie), la production de ROS (mesure de la fluorescence du DCFH) et l'activité kinase de ERK et JNK dans le ventricule ont été déterminées au cours de l'anoxie et de la réoxygénation. Les cœurs ont été traités avec un bloqueur des NO synthases (L-NAME), un donneur de NO (DETA-NONOate), un activateur (diazoxide) ou un inhibiteur (5-HD) des canaux mitoKATP, un inhibiteur non-spécifique des PKC (chélérythrine) ou un piégeur de ROS (MPG).<br />Résultats : L'anoxie et la réoxygénation entraînaient des arythmies (essentiellement d'origine auriculaire) semblables à celles observées chez l'adulte, des troubles de la conduction (blocs auriculo-ventriculaires de 1er, 2ème et 3ème degré) et un ralentissement marqué du couplage excitation-contraction (E-C) ventriculaire. En plus de ces arythmies, la réoxygénation déclenchait le phénomène de Wenckebach, de rares échappements ventriculaires et une sidération myocardique. Aucune fibrillation, conduction rétrograde ou activité ectopique n'ont été observées. Le NO exogène améliorait la récupération postanoxique du couplage E-C ventriculaire alors que l'inhibition des NOS la ralentissait. L'activation des canaux mitoKATP augmentait la production mitochondriale de ROS à la réoxygénation et accélérait la récupération de la conduction (intervalle PR) et du couplage E-C ventriculaire. La protection de ce couplage était abolie par le MPG, la chélérythrine ou le L-NAME. Les fonctions électrique et contractile de tous les coeurs récupéraient après 30-40 min de réoxygénation. L'activité de ERK et de JNK n'était pas modifiée par l'anoxie, mais doublait et quadruplait, respectivement, après 30 min de réoxygénation. Seule l'activité de JNK était diminuée (-60%) par l'activation des canaux mitoKATP. Cet effet inhibiteur était partiellement abolit par le 5-HD.<br />Conclusion: Dans le cœur immature, le couplage E-C ventriculaire semble être un paramètre particulièrement sensible aux conditions d'oxygénation. Sa récupération postanoxique est améliorée par l'ouverture des canaux mitoKATP via une signalisation impliquant les ROS, les PKC et le NO. Une réduction de l'activité de JNK semble également participer à cette protection. Nos résultats suggèrent que les mitochondries jouent un rôle central dans la modulation des voies de signalisation cellulaire, en particulier lorsque les conditions métaboliques deviennent défavorables. Le cœur embryonnaire isolé représente donc un modèle expérimental utile pour mieux comprendre les mécanismes associés à une hypoxie in utero et pour améliorer les stratégies thérapeutiques en cardiologie et chirurgie fœtales.

Objetivo. Considerando a importância da Baixada Santista na manutenção da epidemia de dengue no Estado de São Paulo, realizou-se estudo sobre aspectos da ecologia de Aedes aegypti, enfatizando a fase alada desse inseto. Método. A pesquisa foi desenvolvida no município de Santos, entre janeiro e dezembro de 2003. Imóveis residenciais e não residenciais foram avaliados quanto à presença de recipientes que pudessem servir de habitat para formas imaturas do Aedes aegypti. As larvas (3.º e 4.º estádios) e as pupas foram quantificadas. Paralelamente, foram coletadas e contadas formas aladas do mosquito, e as fêmeas examinadas quanto ao desenvolvimento ovariolar. As formas imaturas e aladas do vetor foram empregadas para estimar índices de infestação. Resultados. 1- Formas imaturas. Registrou-se numerosa variedade de possíveis criadouros do Aedes aegypti. A maioria foi encontrada no ambiente do peridomicílio, que apresentou 93,5% dos recipientes positivos. A positividade média dos tipos de recipientes apresentou diferenças significativas, sendo os maiores valores para pneu (11,9%), outros materiais úteis (5,6%), recipientes para armazenamento de água (4,6%) e outros fixos (4,2%). A positividade dos imóveis para imaturos foi de 2,0%. 2- Formas adultas. A positividade dos imóveis para formas aladas foi de 39,2%. A maioria dos exemplares, 92,4%, foi coletada no intradomicílio. As médias de adultos e de fêmeas por imóvel trabalhado foram de 1,3 e 0,7, respectivamente. Cerca de 90,4% das fêmeas examinadas apresentaram desenvolvimento ovariolar entre as fases III e V de Christophers e Mer. Conclusões. O pneu foi o recipiente que apresentou a maior positividade entre aqueles pesquisados. O ralo foi o mais freqüente entre os positivos. Os valores das estimativas de infestação para adultos foram bem maiores do que para os imaturos. A presença de adultos em todos os meses, sugere que a espécie está estabilizada às condições locais. Corroborou-se a endofilia e a endofagia pela presença dos adultos no intradomicílio e das fêmeas com estádios ovariolares entre III e V de C & M. / Objective.Considering the importance of Baixada Santista in the maintenance of dengue epidemic in São Paulo, study was carried out on the ecological aspects of Aedes aeqypti, emphasizing the adult stage of this insect. Method. The survey was carried out in the municipality of santos, between January to December 2003. Residential and non residential premises were assessed as to the presence of containers which might be used as habitats for Aedes aegypti immatures. Larvae (3rd and 4th instars) and pupae were quantified. Parallelly, adults forms of the mosquito were collected and counted, and females examined as to ovarian development. Both immature and adult forms of the vector were used to estimate infestation indexes. Results. 1- Immature forms. A wide variety of possible breeding sites for Aedes aegypti was registered. Most of them was found in peridomiciliar environment, which presented 93,5% of the positive containers. The average positivity of the types of containers presented significant differences, being the highest values for tyres (11,9%), other useful materials (5,6%), water storage containers (4,6%) and other fixed ones (4,2%). Premises positivity form immature forms was 2,0%. 2- Adults forms. Premises positivity for adult forms was 39,2%. Most of the specimens, 92,4% was collected indoors. Adult and female averages per surveyed premises were 1,3 and 0,7, respectively. Approximately 90,4% of the examined females presented ovarian development between III and V Christophers and Mer phases.Conclusions. Tires showed the higest positivity among all recipients sampled for the study. Rainwater drains were found more frequently positive. estimated values for adult infestation were higher than for immature. The presence of adults throughout the year suggests that the species is adapted to local conditions. Endophily and endophagy were corroborated by the presence of adults inside houses in III to V ovariolar phases of C&M.

Made available in DSpace on 2017-07-25T19:29:49Z (GMT). No. of bitstreams: 1 LucasNatanaelWisch.pdf: 1535950 bytes, checksum: 7b05791c9aa7a46f71ea7e20db744589 (MD5) Previous issue date: 2011-10-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Soybean is one of the main oleaginous crop produced in Brazil. Studies on populational dynamic and immature stage vertical distribution in soybean canopy are very important to improve technology application and control timing. We studied population dynamics and vertical distribution of eggs and larvae of the velvetbean caterpillar, Anticarsia gemmatalis and two Plusiinae species, during the cycle of two soybean cultivars of different growth habits in three sowing dates. Experiments were conducted on Coodetec 206 and BMX Potência RR cultivars during the 2010/2011 growing season in Ponta Grossa, Paraná state. Samples were collected through the crop cycle. Eggs and caterpillars from each third of the plant (bottom, middle and upper) and on different plant structures (main stem, branches, pods and adaxial or abaxial surfaces of leaves) were quantified. Data were analyzed using descriptive statistics and nonparametric Kruskal-Wallis analysis. Plusiinae species occurred simultaneously with A. gemmatalis, which was the predominant species. Highest densities of eggs and larvae of A. gemmatalis were recorded during the second half of January and February. In February we observed the highest densities of Plusiinae. Through the late sowing season we recorded the highest densities of immature stages of Noctuidae. The highest eggs densities for A. gemmatalis and Plusiinae occurred in the middle third (44.03% and 45.99%, respectively) of the canopy followed by the lower (31.96% and 34.18%) and upper portion (24.01% e 19.83%). Small larvae of A. gemmatalis were found mainly in middle (44.08%) and lower third of the plant (36.97%), while medium larvae occurred in higher density in the middle (42.86%) and upper (41.90%) stratum. Meanwhile, most of the large larvae are found in the upper portion of the canopy (63.41%). Highest densities of small, medium and large Plusiinae larvae, we found in middle (43.37%, 44.63% e 44.83%, respectively) and lower (49.46%, 31.40% e 31.03%) third of the canopy. Eggs and caterpillars were found mainly on the abaxial surface of leaflets. / A soja é uma das principais oleaginosas cultivadas no Brasil. Os estudos sobre a ocorrência dos estádios imaturos de Noctuídeos e sua distribuição espacial no perfil da planta são de grande importância para definir o momento de controle e aprimorar a tecnologia de aplicação. O objetivo deste trabalho foi avaliar a flutuação populacional e a distribuição vertical de ovos e larvas dos principais Noctuídeos, Anticarsia gemmatalis e Plusiinae, durante o ciclo de duas cultivares de soja de diferentes hábitos de crescimento em três épocas de semeadura. Os experimentos foram conduzidos durante a safra 2010/2011 no município de Ponta Grossa – PR, em três épocas diferentes de semeadura das cultivares Coodetec 206 e BMX Potência RR. As amostragens foram realizadas durante todo o ciclo da cultura em diferentes alturas da planta (terço superior, médio e inferior) e em diferentes estruturas da planta (haste principal, ramos, vagens e face adaxial ou abaxial das folhas). Os dados foram analisados através da estatística descritiva e do teste não-paramétrico de Kruskal-Wallis. As espécies de Plusiinae ocorreram simultaneamente a A. gemmatalis, a qual foi a espécie predominante. As maiores densidades de ovos e lagartas de A. gemmatalis foram registradas na segunda quinzena de janeiro e durante o mês de fevereiro, mês em que se observou maior densidade de Plusiinae. As semeaduras mais tardias apresentaram as maiores densidades de estádios imaturos de Noctuídeos. A maior oviposição, tanto para A. gemmatalis quanto a Plusiinae ocorreu no terço médio (44,03% e 45,99%, respectivamente) seguido pelo inferior (31,96% e 34,18%) e superior (24,01% e 19,83%). As lagartas pequenas de A. gemmatalis foram encontradas principalmente nos terços médio (44,08%) e inferior (36,97%), enquanto as lagartas médias ocorreram em maior densidade nos estratos médio (42,86%) e superior (41,90%) e os indivíduos grandes, na região apical (63,41%) do dossel. A maior densidade de lagartas de Plusiinae pequenas, médias e grandes foi observada no terço médio (43,37%, 44,63% e 44,83%, respectivamente) e inferior (49,46%, 31,40% e 31,03%). Os ovos e as lagartas dos Noctuídeos foram encontrados, principalmente, na face abaxial dos folíolos.

A Solanum lycocarpum é uma planta encontrada em quase todos os estados do Brasil, podendo ser ingerida por animais em idade fértil e em condições naturais. Os frutos desta planta possuem glicoalcalóides esteroidais com propriedades semelhantes aos esteróides. Neste estudo investigou-se os efeitos na esfera reprodutiva causados pela ingestão de S. lycocarpum durante a puberdade de ratos. Os frutos secos foram administrados na ração (10%) desde o desmame até a idade adulta (70dias). Foram avaliados o peso corpóreo e de órgãos, o comportamento e a orientação sexual, os níveis de hormônios sexuais nas fezes, a bioquímica sérica, os níveis de neurotransmissores centrais e os achados anatomopatológico, tanto de ratos machos como de fêmeas. Observou-se os seguintes resultados: 1) Redução no peso corpóreo dos machos e das fêmeas; 2) Em machos, o peso relativo aumentou nos epidídimos, vesícula seminal e testículos; 3) Não houve diferenças no hemograma entre os grupos controle e experimental de ambos os sexos; 4) Alterações na bioquímica sangüínea sugerem leve toxicidade em células musculares e hepática; 5) Em fêmeas, não constatou-se nenhuma alteração no ciclo estral e no comportamento sexual; enquanto nos machos houve melhora do comportamento sexual e 6) Os níveis de neurotransmissores do estriado foi modificado mas não os do hipotálamo. Esses achados indicam que a exposição a S. lycocarpum durante a puberdade prejudicou parâmetros da esfera reprodutiva, em particular, dos machos. / Solanum lycocarpum St. Hil, a toxic plant common in almost all states of Brazil, may be consumed by animals in fertile age and in natural condition. The fruits of this plant contain steroidal glycoalkaloids with steroid-like properties. Presently the reproductive effects of S. lycocarpum fruit ingestion during puberty were investigated. The dried fruits were administered in the diet (10%) from the weaning up to adult age (70 days). The body and organs weights, sexual behavior as well as sexual orientation, the feces hormonal levels, hemogram and biochemical blood evaluations, hypothalamic and striatal neurotransmitter levels, and anatomopathological studies of male and female rats were performed. The results showed: 1) a reduced body weight in male and female; 2) in male, an increased epydidimis, seminal vesicle and testis relative weights; 3) no differences of controls and experimental groups of both sex in the hemogram; 4) blood biochemical alterations meaning slight toxicity in muscular and hepatic cells; 5) in female, no interference was detected in estrous cycle and sexual behavior; an improvement of male sexual behavior was observed; 6) that striatal neurotransmitter levels were modified but not in the hypothalamus. These results indicate that exposure to S. lycocarpum during puberty prejudiced the reproductive system, particularly in male rats.

A Solanum lycocarpum é uma planta encontrada em quase todos os estados do Brasil, podendo ser ingerida por animais em idade fértil e em condições naturais. Os frutos desta planta possuem glicoalcalóides esteroidais com propriedades semelhantes aos esteróides. Neste estudo investigou-se os efeitos na esfera reprodutiva causados pela ingestão de S. lycocarpum durante a puberdade de ratos. Os frutos secos foram administrados na ração (10%) desde o desmame até a idade adulta (70dias). Foram avaliados o peso corpóreo e de órgãos, o comportamento e a orientação sexual, os níveis de hormônios sexuais nas fezes, a bioquímica sérica, os níveis de neurotransmissores centrais e os achados anatomopatológico, tanto de ratos machos como de fêmeas. Observou-se os seguintes resultados: 1) Redução no peso corpóreo dos machos e das fêmeas; 2) Em machos, o peso relativo aumentou nos epidídimos, vesícula seminal e testículos; 3) Não houve diferenças no hemograma entre os grupos controle e experimental de ambos os sexos; 4) Alterações na bioquímica sangüínea sugerem leve toxicidade em células musculares e hepática; 5) Em fêmeas, não constatou-se nenhuma alteração no ciclo estral e no comportamento sexual; enquanto nos machos houve melhora do comportamento sexual e 6) Os níveis de neurotransmissores do estriado foi modificado mas não os do hipotálamo. Esses achados indicam que a exposição a S. lycocarpum durante a puberdade prejudicou parâmetros da esfera reprodutiva, em particular, dos machos. / Solanum lycocarpum St. Hil, a toxic plant common in almost all states of Brazil, may be consumed by animals in fertile age and in natural condition. The fruits of this plant contain steroidal glycoalkaloids with steroid-like properties. Presently the reproductive effects of S. lycocarpum fruit ingestion during puberty were investigated. The dried fruits were administered in the diet (10%) from the weaning up to adult age (70 days). The body and organs weights, sexual behavior as well as sexual orientation, the feces hormonal levels, hemogram and biochemical blood evaluations, hypothalamic and striatal neurotransmitter levels, and anatomopathological studies of male and female rats were performed. The results showed: 1) a reduced body weight in male and female; 2) in male, an increased epydidimis, seminal vesicle and testis relative weights; 3) no differences of controls and experimental groups of both sex in the hemogram; 4) blood biochemical alterations meaning slight toxicity in muscular and hepatic cells; 5) in female, no interference was detected in estrous cycle and sexual behavior; an improvement of male sexual behavior was observed; 6) that striatal neurotransmitter levels were modified but not in the hypothalamus. These results indicate that exposure to S. lycocarpum during puberty prejudiced the reproductive system, particularly in male rats.

Les crises fébriles représentent l'évènement épileptique le plus fréquent dans l'espèce humaine et touchent 5 % de la population. Bien que la bénignité de leur pronostic ait été établie par de nombreuses études prospectives, une infime proportion de ces enfants va développer un syndrome d'épilepsie mésio-temporale avec sclérose de l'hippocampe. L'hypothèse de ce travail est que la crise fébrile serait nécessaire mais non suffisante au développement de ce type d'épilepsie, un second élément au potentiel épileptogène serait ainsi indispensable. Notre travail a montré que les crises hyperthermiques chez la souris constituent une bonne approche pour modéliser les crises fébriles de l'enfant. Nous avons ainsi montré que les conséquences des crises hyperthermiques étaient différentes selon la séquence de survenue par rapport au second évènement épileptogène. (i) Lorsque la crise hyperthermique précède l'injection de kaïnate dans l'hippocampe, elle accélère la phase d'épileptogenèse et majore la dispersion des cellules granulaires du gyrus denté, sans modifier la perte cellulaire des neurones pyramidaux de la corne d'Ammon. Elle entraine également une modification du pattern des décharges rythmiques hippocampiques lors de la phase chronique, sans modifier la fréquence ni la durée de ces décharges. (ii) Lorsque la crise hyperthermique succède à la présence d'une dysplasie de la partie CA3 de la corne d'Ammon d'origine génétique, elle semble diminuer le risque de crise chez les animaux KO pour le gène de la double cortine. Pourtant, l'augmentation de la fréquence d'une néo-expression du NPY par les cellules granulaires, chez les animaux Hz pour cette mutation, suggère que les crises hyperthermiques favoriseraient la route vers une épilepsie, tout en activant la mise en place de mécanismes protecteurs contre la survenue des crises. En conclusion, les crises hyperthermiques faciliteraient la route vers l'épilepsie, mais n'auraient pas d'effet facilitateur sur la route vers la crise.